Synthesis and Reactivity Study of Low-Valent Group 14 Metal Compounds Supported by Pyridyl-1-azaallyl and Iminophosphoranyl Ligands

This thesis is focused on three areas: (i) the reactivities of pyridyl-1-azaallyl germanium(II) chloride; (ii) the synthesis and reactivities of pyridyl-1-azaallyl germanium(I) dimer; (iii) the synthesis and reactivities of low-valent main group 14 metal complexes and metallavinylidenes derived from phosphoranoimines.;Chapter 1 describes the reactivities of pyridyl-1-azaallyl germanium(II) chloride [{N(SiMe3)C(Ph)C(SiMe3)(C5H 4N-2)}GeCl] (66). The reaction of 66 with Na[M(eta5-C5H5)(CO)3]˙2DME (M = Mo or W) affords heterobimetallic germylenes 76 and 77 which contain a germanium(II)-metal single bond. A Cp-substituted germylene was prepared from the reaction of 66 with sodium cyclopentadienylide. The Lewis base behavior of 66 toward bulky borane was investigated. Treatment of 66 with B(C6F5)3 leads to the formation of a Lewis acid-base adduct 79. Furthermore, the ligand transfer reaction of 66 with GaCl3 and InCl3 were studied. In addition, the reaction of 66 with water affords [{HNC(Ph)CH(C5H4N-2)}GeCl] ( 82).;Chapter 2 describes the reduction chemistry of 66. Treatment of 66 with excess magnesium tunings affords a mixture of products [N(SiMe3)C(Ph)C(SiMe3)- (C5H4N-2)Mg(micro-Cl)(THF)] 2 (110) and [C(Ph)C(SiMe3)(C5H 4N-2)]2Ge2 (111). The reaction of 66 with an excess of lithium metals leads to a mixture of germanium(I) dimers [C(Ph)C(SiMe3)(C5H4N-2)]2Ge 2 (111) and [N(SiMe3)C(Ph)C(SiMe3)- (C5H4N-2)]2Ge2 (112). When compound 66 was treated with one equivalent of potassium graphite, compound 112 was obtained as the major product. The reaction of 112 with azobenzene affords the 1,2-digermylene hydrazinide [PhNGe{N(SiMe3) C(Ph)C(SiMe3)(C5H4N-2)}] 2 (113). The Lewis base behaviour of 112 was studied. Treatment of 112 with one equivalent of diironnonacarbonyl gives a new unsymmetric germanium(I) dimer [{N(SiMe3)C(Ph)C(SiMe 3)(C5H4N-2)(Fe(CO)4)- Ge-Ge{N(SiMe 3)C(Ph)C(SiMe3)(C5H4N-2)}] ( 114), while the reaction of 112 with two equivalent of diironnonacarbonyl leads to the formation of [{N(SiMe3)C- (Ph)C(SiMe 3)(C5H4N-2)Fe(CO)4)Ge]2 (115). In addition, the reaction of 112 with sulfur affords the first germanium analogue of a dithiocarboxylic acid anhydride.;Chapter 3 deals with the synthesis of group 14 metal(II) complexes supported by iminophosphoranyl ligands. The synthesis of germanium(II) and tin(II) compounds derived from Ph2P(2-CH2Py)=NSiMe3 ( 119) and H2C(PPh2=NSiMe3)2 (121) are described. Furthermore, the coordination chemistry of the hemilabile ligand Ph2PCH2(PPh2=NSiMe 3) (131) was investigated. Iminophosphoranyl phosphine 131 undergoes metalation with BunLi and Bun 2Mg to give the lithium complex [Li{CH(PPh2)(PPh2=NSiMe 3)}(THF)2] (194) and the magnesium complex [Mg{CH-(PPh 2)(PPh2=NSiMe3)}2] (193), respectively. 1,3-distannylcyclobutane 196 and 1,3-diplumbacyclobutane 200 were prepared from the reaction of 194 with the corresponding metal(II) chlorides. The reaction of 194 with GeCl2˙(dioxane) leads to a tri-nuclear heterocyclic cage compound 195. In addition, the trapping reaction of 196 with diironnonacarbonyl affords the phoshpine-stabilized stannavinylidene 197..;Chapter 4 describes the conclusion of the first three chapters.